Mix the dry ingredients: Combine the dry ingredients together in a large bowl: cornstarch, citric acid, SLSA and baking soda. (I recommend glass or metal bowls.) I used a wooden spoon to carefully mix and fold everything together. Mix the wet ingredients: Measure the coconut oil into a small microwave safe bowl. Put it in the microwave for 30-60 seconds to melt it down. Mix in the polysorbate 80 and the essential oils.
Combine the wet and dry ingredients: Pour the wet ingredients into the large bowl with the dry ingredients. I used a wooden spoon to start out but then switched to using my hands to combine it the rest of the way. Make sure to crush any large pieces you feel until they are gone. (Refer to notes below about consistency and what to do if your mixture is too dry.)
Add mica powder: If you want to do more than one color for your bath bombs, divide the mixture into multiple bowls. I did green and gold. A little goes a long way so start with 1/2 teaspoon and then add more if you want a darker color.
Fill the pots: Use a small metal spoon to scoop the mixture into your pot. Then use the spoon to push it down a little. Push it down the rest of the way using your thumb. Important: You will need to add the bath bomb mixture in layers, compacting each layer as you go. Just keep scooping and pressing, changing the colors as you go. Remember to add the trinket about half way through filling the pot.
Let the bath bombs dry: The great thing about these pot of gold bath bombs is that you don't have to worry about taking the bombs out of a mold. All you need to do is give them time to dry (overnight is a good rule of thumb) and then they are ready to be used.